Cameras using CCD's are now becoming commonplace. However, a significant amount of logic circuitry is generally required to be used in conjunction with CCD elements, for sampling and timing purposes. Clearly, there are many different sizes and types of CCD which require different logic circuits, clock waveforms and speeds etc. Furthermore, with the onset of high resolution systems, CCD's of even greater density and speed will be required. Thus, whenever one CCD in a camera is to be replaced by another of different type, for upgrading or other purposes, it is also necessary to replace the logic circuitry which provides the waveforms for that CCD. This can be inconvenient and prohibitively expensive.
It is also occasionally observed that a CCD camera operating with a very high gain shows a vertical fixed pattern on the picture. This is thought to be due to feed-through from the counter in the CCD gate array which is arranged to count at pixel rate. During the counting process different numbers of counter stages will toggle at any time and this causes variations in power supply, leading to perturbations which result in small amounts of amplitude and/or pulse width modulation on the CCD waveforms. An apparatus is also required which solves this problem in a straight forward manner.